/*	$OpenBSD: egetopt.c,v 1.9 2013/11/26 13:19:07 deraadt Exp $	*/

/*-
 * Copyright (c) 1991 Keith Muller.
 * Copyright (c) 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Keith Muller of the University of California, San Diego.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "extern.h"

/*
 * egetopt:	get option letter from argument vector (an extended
 *		version of getopt).
 *
 * Non standard additions to the ostr specs are:
 * 1) '?': immediate value following arg is optional (no white space
 *    between the arg and the value)
 * 2) '#': +/- followed by a number (with an optional sign but
 *    no white space between the arg and the number). The - may be
 *    combined with other options, but the + cannot.
 */

int eopterr = 1; /* if error message should be printed */
int eoptind = 1; /* index into parent argv vector */
int eoptopt;     /* character checked for validity */
char *eoptarg;   /* argument associated with option */

#define BADCH (int)'?'
#define EMSG ""

int egetopt(int nargc, char *const *nargv, const char *ostr) {
  static char *place = EMSG; /* option letter processing */
  char *oli;                 /* option letter list index */
  static int delim;          /* which option delimiter */
  char *p;
  static char savec = '\0';

  if (savec != '\0') {
    *place = savec;
    savec = '\0';
  }

  if (!*place) {
    /*
     * update scanning pointer
     */
    if ((eoptind >= nargc) ||
        ((*(place = nargv[eoptind]) != '-') && (*place != '+'))) {
      place = EMSG;
      return (-1);
    }

    delim = (int)*place;
    if (place[1] && *++place == '-' && !place[1]) {
      /*
       * found "--"
       */
      ++eoptind;
      place = EMSG;
      return (-1);
    }
  }

  /*
   * check option letter
   */
  if ((eoptopt = (int)*place++) == (int)':' || (eoptopt == (int)'?') ||
      !(oli = strchr(ostr, eoptopt))) {
    /*
     * if the user didn't specify '-' as an option,
     * assume it means EOF when by itself.
     */
    if ((eoptopt == (int)'-') && !*place) return (-1);
    if (strchr(ostr, '#') &&
        (isdigit((unsigned char)eoptopt) ||
         (((eoptopt == (int)'-') || (eoptopt == (int)'+')) &&
          isdigit((unsigned char)*place)))) {
      /*
       * # option: +/- with a number is ok
       */
      for (p = place; *p != '\0'; ++p) {
        if (!isdigit((unsigned char)*p)) break;
      }
      eoptarg = place - 1;

      if (*p == '\0') {
        place = EMSG;
        ++eoptind;
      } else {
        place = p;
        savec = *p;
        *place = '\0';
      }
      return (delim);
    }

    if (!*place) ++eoptind;
    if (eopterr) {
      if (!(p = strrchr(*nargv, '/')))
        p = *nargv;
      else
        ++p;
      (void)fprintf(stderr, "%s: illegal option -- %c\n", p, eoptopt);
    }
    return (BADCH);
  }
  if (delim == (int)'+') {
    /*
     * '+' is only allowed with numbers
     */
    if (!*place) ++eoptind;
    if (eopterr) {
      if (!(p = strrchr(*nargv, '/')))
        p = *nargv;
      else
        ++p;
      (void)fprintf(stderr, "%s: illegal '+' delimiter with option -- %c\n", p,
                    eoptopt);
    }
    return (BADCH);
  }
  ++oli;
  if ((*oli != ':') && (*oli != '?')) {
    /*
     * don't need argument
     */
    eoptarg = NULL;
    if (!*place) ++eoptind;
    return (eoptopt);
  }

  if (*place) {
    /*
     * no white space
     */
    eoptarg = place;
  } else if (*oli == '?') {
    /*
     * no arg, but NOT required
     */
    eoptarg = NULL;
  } else if (nargc <= ++eoptind) {
    /*
     * no arg, but IS required
     */
    place = EMSG;
    if (eopterr) {
      if (!(p = strrchr(*nargv, '/')))
        p = *nargv;
      else
        ++p;
      (void)fprintf(stderr, "%s: option requires an argument -- %c\n", p,
                    eoptopt);
    }
    return (BADCH);
  } else {
    /*
     * arg has white space
     */
    eoptarg = nargv[eoptind];
  }
  place = EMSG;
  ++eoptind;
  return (eoptopt);
}
